全尺寸高压除鳞喷嘴内部流场特性的数值模拟

Numerical simulation of internal flow field characteristics of full-scale high-pressure descaling nozzle

为充分考虑过滤器和稳流器对高压除鳞喷嘴内部流场的影响,利用CFD对全尺寸除鳞喷嘴进行数值建模并对内部流场特性进行研究。分析喷嘴结构以及入口压力对喷嘴内部流场特性的影响,揭示中轴线流场分布特征,阐明出口速度与入口压力之间的数学关系。结果表明,与简化模型相比,全尺寸模型的内部压力较低,二者之间存在(2~4)×10^(5)Pa的偏差;对于全尺寸模型,喷嘴内部压力衰减主要发生在收缩段末端以及喷头出口处,其中当水流经过滤器与稳流器时压力衰减约为0.6 MPa;对于相同工况下不同区域,喷头部分的速度变化远大于过滤器与收缩段部分;随着入口压力的增加,内部流场压力衰减逐渐增大,同时整个内部流场的速度也相应增大,且压力越大,速度变化越明显,即喷嘴入口压力与出口速度满足正相关。

In order to fully consider the influence of filters and flow stabilizers on the internal flow field of high-pressure scale-removal nozzles,numerical modeling of full-size scale-removal nozzles and study of the internal flow field characteristics were carried out using CFD.The influence of nozzle structure and inlet pressure on the internal flow field characteristics of the nozzle was analyzed to reveal the characteristics of the flow field distribution in the central axis and to clarify the mathematical relationship between the exit velocity and inlet pressure.The results show that,compared with the simplified model,the internal pressure of the full-size model is lower,and there is a deviation of(2-4)×10^(5) Pa between the two.For the full-size model,the internal pressure decay of the nozzle mainly occurs at the end of the shrinkage section and the nozzle outlet,where the pressure decay is about 0.6 MPa when the water flows through the filter and stabilizer.For different regions,the same conditions,the speed of the nozzle section.The change is much greater than the filter and shrinkage section.With the increase in the inlet pressure,the internal flow field pressure decay gradually increased,while the entire internal flow field speed also increased accordingly,and the greater the pressure,the more obvious the change in speed,that is,the nozzle inlet pressure and exit speed to meet the positive correlation.